The township is under a water boil advisory. They decided the way to inform people was on the website, through phone if you have a phone on your water account, through a system no one knew existed, or Facebook.
They’re offering a case of water per household for free though!
That announcement was only through Facebook. Great. All gone.
That can easily be done by cell broadcasts (which can absolutely have different stages of priority nowadays), mass-SMS (every cellphone that first registers in an affected area gets a SMS, via designated disaster management apps, by placing handouts on peoples doors (you usually do that by identify people at risks e.g. homecare patients, then you go by high to low risk areas - depending on the search of the contamination) and last but not least a few trucks with loudspeakers (even regular cop cars do) do wonders.
What happens here if someone is not at home when called, is not an actual customer of the water company, etc.?
There are dozens of better ways than how this was handled in OPs case.
Source: I consult community and disaster response organisations on this stuff.